Single-layer feed waveguide consisting of posts for plane TEM wave excitation in parallel plates

The authors propose a novel feed structure to excite a plane TEM wave in a parallel-plate waveguide. The feed waveguide is composed of densely arrayed posts on the same layer as the parallel plate. The posts can be easily fabricated at low cost by making metalized via holes in a grounded dielectric substrate. Such a procedure results in a quite simple fabrication of the antenna. The feed waveguide is designed to obtain a uniform division, which is confirmed by measurements on a 40-GHz band model.